In contrast to the flexible rotation of magnetisation direction in ferromagnets, the spontaneous polarisation in ferroelectric materials is highly confined along the symmetry-allowed directions. Accordingly, chirality at ferroelectric domain walls was treated only at the theoretical level so far and its real appearance is still a mystery. Here a joint group of researchers by EPFL-Swiss Federal Institute of Technology in Lausanne, Xi'an Jiaotong University and the Ernst Ruska-Centre in Jülich report a Néel-like domain wall imaged by atom-resolved transmission electron microscopy in Ti-rich ferroelectric Pb(Zr1-xTix)O3 crystals, where nanometre-scale monoclinic order coexists with the tetragonal order. The formation of such domain walls is interpreted in the light of polarisation discontinuity and clamping effects at phase boundaries between the nesting domains. Phase field simulation confirms that the coexistence of both phases as encountered near the morphotropic phase boundary promotes the polarisation to rotate in a continuous manner. Experimental results provide a further insight into the complex domain configuration in ferroelectrics, and establish a foundation towards exploring chiral domain walls in ferroelectrics.
Further reading: Xian-Kui Wei, Chun-Lin Jia, Tomas Sluka, Bi-Xia Wang, Zuo-Guang Ye, Nava Setter. "Néel-like domain walls in ferroelectric Pb(Zr,Ti)O3 single crystals". Nature Communications, 7: 12385, 2016.
Link: http://www.nature.com/articles/ncomms12385
